For testing of urine, blood, interstitial fluid or other body fluids, it is customary to use consumables containing detection reagents that effect a detection reaction when ex-posed to a body fluid sample. The detection reaction can, for example, lead to fluorescence or a color change that can be analyzed by photometry in order to determine an analyte concentration. Also known are detection reactions for electrochemical de-termination of an analyte concentration. In general, a detection reaction leads to a change in a parameter that can be measured physically, whereby the intensity of the change depends on the analyte concentration to be measured.
In a typical case, the detection sensitivity varies substantially between production batches of consumables containing detection reagents. For this reason, there is a need to have calibration data in order to be able to determine an analyte concentration with sufficient accuracy for medical applications when analyzing the result of a detection reaction from the extent of the change of a physical parameter, for example a change of color. Calibration data of this type is usually determined for each production batch using calibration liquids of known analyte concentration and a corresponding calibration information is stored on a data carrier that is distributed jointly with the consumable.
For this reason, hand-held devices of systems for measuring an analyte concentration of a body fluid sample usually contain, aside from a measuring facility for measuring the result of a detection result, a reading facility for reading calibration information from a data carrier. For example, one known system provides a bar code containing a calibration information, affixed to the outside of a drum cartridge containing the consumables. An exemplary disclosure is from EP 1 574 855. However, such systems are rather inflexible.
The production of hand-held devices of systems for measuring the analyte concentration in a body fluid sample is expensive since there is a need to have a highly-precise measuring facility and a processor as a control and analytical unit. As progress is made in the production of consumables with detection reagents, the software that was used to program the processor at the time the hand-held device was delivered may no longer meet the requirements of improved consumables, since, for example, different measuring parameters, for example different measuring times or even different measuring or analytical procedures may be needed. However, changing the programming of the microprocessor is not feasible in the hand-held device known, for example from EP 1574 855 A1, such that progress made with regard to the measuring of the analyte concentration of a body fluid sample usually necessitates the purchase of a new hand-held device. Moreover, possibly existing software errors can be rectified only by a cost-intensive recall action.
It is therefore the object of the invention to further improve upon a system for measuring an analyte concentration of a body fluid sample of the type specified above. In particular, it is the object of the invention to devise a way allowing even medical laymen to carry out a reliable measurement of an analyte concentration of a body fluid sample at low cost.